Amp output is wired in series vs parallel?

Just read the Sterophile review of the 1000 watt monoblocks from Bryston, the 28B SST. it mentioned that each monoblock is two amps bridged, wired in series. But they also mention that if you want to play low impedance speakers of 4 or 2 ohms, you should have Bryston wire the amps in paralell at the factory.

My question is, does the amp being wired in series or paralell affect the power rating of the amp? What is the effect sonically on the amp if it wired parallell vs series?

The link to the review is below:
On the SST, parallel operation is a factory option, not a switch like the earlier versions. Should be an easy mod.
Mitch4t, why not try and then post your findings, if you don't you will never know.

Do you know of anyone else using the same speaker you have, if so what have they tried.
This is an old thread but I was playing with this on my used 7BST’s I just picked up.  I bi-wired to my speakers. My assumption is I now have a fight current connection to the LF binding posts and a high current connection to the HF binding posts.  Is this assumption correct?

that being said, I don’t see any speaker manufacturers listing the impedance of the LF and HF connections individually.  They only list the speaker as a whole or “nominal 4 ohms”

I am guessing I can connect one of those Parts Express speaker testers to it to see what the impedance curve looks like.  I am assuming they will be 8 ohm loads and with the bridging clips in they would parallel down to 4 ohm loads.  
I have seen different specs on the 7B’s output.  So figuring out what the potential wattage is when in Parallel mode is getting tricky.  The factories final check out slip indicated the output at something like 615 watts.  The literature says 800 watts.  
Either way I felt the bottom end on my speakers seemed to play a little better with the system bi-wired in parallel mode.